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401. The role of membrane fluidity changes and thiobarbituric acid-reactive substrances production in the inhibition of cerebral cortex Na+/K+-ATPase activity

Creator:
Hana Rauchová, Zdeněk Drahota, and Jitka Koudelová
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Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, cerebral cortex membranes, lipid peroxidation, membrane fluidity, 14, and 612
Language:
English
Description:
Lipid peroxidation of rat cerebral cortex membranes was induced by Fe2+/ADP and ascorbate. The rate of Na+/K+-ATPase inhibition was correlated with the increase of thiobarbituric acid-reactive substances (TBARS) and conjugated dienes (CD) and with membrane fluidity changes. Our data showed that membrane fluidity changes (evaluated by fluorescence steady-state anisotropy measurements) can participate in Na+/K+-ATPase inhibition during the initial period of lipid peroxidation process, whereas during the following period the enzyme inhibition correlates only with TBARS and CD production., H. Rauchová, Z. Drahota, J. Koudelová., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

402. The time-course of agonist-induced solubilization of trimetric Gqα/G11α proteins resolved by two-dimensional electrophoresis

Creator:
Dana Durchánková, Jiří Novotný, and Petr Svoboda
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Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, bílkoviny, elektroforéza, thyrotr, physiology, proteins, electrophoresis, G proteins, solubilization, Gqα/G11α, thyrotropin-releasing hormone, TRH receptor, 14, and 612
Language:
English
Description:
Prolonged agonist stimulation results in specific transfer of activated Gα subunits of Gqα/G11α family from particulate membrane fraction to soluble (cytosol) cell fraction isolated as 250 000 x g supernatant. In this study, we have used 2D electrophoresis for more defined resolution of Gα subunits of Gqα/G11α family and followed the time course of solubilization effect. The small signal of soluble G proteins was already detected in control, hormone-unexposed cells. Hormone stimulation resulted in a slow but continuous increase of both intensity and number of immunoreactive signals/spots of these G proteins (10, 30, 60, 120 and 240 min). At longer times of agonist exposure (>2 hours), a marked increase of Gqα/G11α proteins was detected. The maximal level of soluble Gqα/G11α proteins was reached after 16 hours of continuous agonist exposure. At this time interval, eight individual immunoreactive signals of Gqα/G1 α proteins could be resolved. The relative proportion among these spots was 15:42:10:11:7:7:2:5. Solubilization of this class of Gα proteins was thus observed after prolonged agonist stimulation only, induced by ultra high concentration of hormone and in cells expressing a large number of GPCRs. Our data therefore rather indicate tight/persisting binding of Gqα/G11α proteins to the membrane., D. Durchánková, J. Novotný, P. Svoboda., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

403. The VO2-on kinetics in constant load exercise sub-anaerobic threshold reflects endothelial function and dysfunction in muscle microcirculation

Creator:
Maione, D., Cicero, A. F. G., Bacchelli, S., Cosentino, E. R., Degli Esposti, D., Manners, D. N., Rinaldi, E. R., Rosticci, M., Senaldi, R., Ambrosioni, E., and Borghi, C.
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Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, anaerobic threshold, constant load exercise, endothelial function, O2 consumption, 14, and 612
Language:
English
Description:
To propose a test to evaluate endothelial function, based on VO 2 on-transition kinetics in sub -anaerobic threshold (AT) constant load exercise, we tested healthy subjects and patients with ischemic -hypertensive cardiopathy by two cardiopulmonary te sts on a cycle ergometer endowed with an electric motor to overcome initial inertia: a pre-test and, after at least 24 h, one 6 min constant load exercise at 90 % AT. We measured net phase 3 VO2-on kinetics and, by phase 2 time constant (τ), valued endothe lial dysfunction. We found shorter τ in repeated tests, shorter time between first and second test, by persisting endothelium -dependent arteriolar vasodilatation and/or several other mechanisms. Reducing load to 80 % and 90 % AT did not produce significant changes in τ of healthy volunteers, while in heart patients an AT load of 70 %, compared to 80 % AT, shortened τ(∆=4.38±1.65s, p=0.013). In heart patients, no correlation was found between NYHA class, ejection fraction (EF), and the two variables derived from incremental cycle cardio - pulmonary exercise, as well as between EF and τ; while NYHA class groups were well correlated w ith τ duration (r=0.92, p=0.0001). Doxazosin and tadalafil also significantly reduced τ. In conclusion, the O2 consumption kinetics during the on transition of constant load exercise below the anaerobic threshold are highly sensitive to endothelial functi on in muscular microcirculation, and constitute a marker for the evaluation of endothelial dysfunction. and D. Maione, A. F. G. Cicero, S. Bacchelli, E. R. Cosentino, D. Degli Esposti, D. N. Manners, E. R. Rinaldi, M. Rosticci, R. Senaldi, E. Ambrosioni, C. Borghi.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

404. Time of VO2max plateau and post-exercise oxygen consumption during incremental exercise testing in young mountain bike and road cyclists

Creator:
Hebisz, P, Hebisz, R, Borkowski, J, and Zatoń, M
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Subject:
cyklistika, fyziologie, cycling, physiology, time of maximal oxygen plateau, anaerobic metabolism, 14, and 612
Language:
English
Description:
The purpose of this study was to compare markers of glycolytic metabolism in response to the Wingate test and the incremental test in road and mountain bike cyclists, who not different performance level and aerobic capacity. All cyclists executed the Wingate test and incremental test on a cycle ergometer. Maximal power and average power were determined during the Wingate test. During the incremental test the load was increased by 50 W every 3 min, until volitional exhaustion and maximal aerobic power (APmax), maximal oxygen uptake (VO2max), and time of VO2max plateau (Tplateau) were determined. Post-exercise measures of oxygen uptake (VO2post), carbon dioxide excretion, (VCO2post), and the ratio between VCO2/VO2 (RERpost) were collected for 3 min immediately after incremental test completion. Arterialized capillary blood was drawn to measure lactate (La-) and hydrogen (H+) ion concentrations in 3 min after each test. The data demonstrated significant differences between mountain bike and road cyclists for Tplateau, VO2post, VCO2post, La- which was higher-, and RERpost which was lower-, in mountain bike cyclists compare with road cyclists. No differences were observed between mountain bike and road cyclists for APmax, VO2max, H+ and parameters measured in the Wingate test. Increased time of VO2max plateau concomitant to larger post-exercise La- and VO2 values suggests greater anaerobic contribution during incremental testing efforts by mountain bike cyclists compared with road cyclists., P. Hebisz, R. Hebisz, J. Borkowski, M. Zatoń., and Obsahuje bibliografii
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

405. Time-course of tissue factor plasma level in patients with acute coronary syndrome

Creator:
Josef Bis, Jan Vojáček, Jan Dušek, Miroslav Pecka, Vladimír Palička, Josef Šťásek, and Jan Malý
Format:
bez média and svazek
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, akutní koronární syndromy, arteriální trombóza, physiology, acute coronary syndromes, coronary artery disease, tissue factor, 14, and 612
Language:
English
Description:
Enhanced expression of tissue factor (TF) may result in thrombosis contributing to acute clinical consequences of coronary artery disease. Several studies demonstrated elevated plasma levels of TF in patients with acute coronary syndrome (ACS). The aim of our study was to compare the concentrations of TF in coronary sinus (CS), proximal part of the left coronary artery (LCA) and peripheral vein (PV) of patients with ACS and stable coronary artery disease (SCAD). Time course of the TF plasma levels in PV was followed on day 1 and day 7 after index event of ACS presentation and was compared to day 0 values. No heparin was given prior to the blood sampling. Twenty-nine patients in the ACS group (age 63.6±10.8 years, 20 males, 9 females) and 24 patients with SCAD (age 62.3±8.1 years, 21 males, 3 females) were examined. TF plasma level was significantly higher in patients with ACS than in those with SCAD (239.0±99.3 ng/ml vs. 164.3±114.2 ng/ml; p=0.016). There was no difference in TF plasma levels in PV, CS and LCA (239.0± 99.3 ng/ml vs. 253.7±131.5 ng/ml vs. 250.6±116.4 ng/ml, respectively). TF plasma levels tended to decrease only non-significantly on the day 7 (224.4± 109.8 ng/ml). Significant linear correlation between TF and high sensitivity CRP (hs-CRP) levels on day 0 was found. In conclusion, TF plasma levels are elevated in patients with ACS not only locally in CS but also in systematic circulation. Our data support the relationship between TF production and proinflammatory mediators., J. Bis ... [et al.]., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

406. Tolerance to acute ischemia in adult male and female spontaneously hypertensive rats

Creator:
Josef Bešík, Ondrej Szárszoi, Jaroslav Kuneš, Ivan Netuka, Jan Malý, František Kolář, Jan Pirk, and Bohuslav Ošťádal
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Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, hypertenze, pohlavní rozdíly, physiology, hypertension, sex differences, srdeční tolerance, ischemické / reperfuzní poškození, spontánně hypertenzivní krysy, genderové rozdíly, cardiac tolerance, ischemia / reperfusion injury, spontaneously hypertensive rats, gender differences, 14, and 612
Language:
English
Description:
Clinical and experimental studies have repeatedly indicated that overloaded hearts have a higher vulnerability to ischemia/reperfusion injury. The aim of the present study was to answer the question whether the degree of tolerance to oxygen deprivation in hearts of spontaneously hypertensive rats (SHR) may be sex-dependent. For this purpose, adult SHR and their normotensive control Wistar Kyoto (WKY) rats were used. The isolated hearts were perfused according to Langendorff at constant pressure (proportionally adjusted to the blood pressure in vivo). Recovery of contractile parameters (left ventricular systolic, diastolic and developed pressure as well as the peak rate of developed pressure) was measured during reperfusion after 20 min of global no-flow ischemia in 5 min intervals. Mean arterial blood pressure was measured by direct puncture of carotid artery under light ether anesthesia in a separate group of animals. The degree of hypertension was comparable in both sexes of SHR. The recovery of contractile functions in SHR males and females was significantly lower than in WKY rats during the whole investigated period. There was no sex difference in the recovery of WKY animals; on the other hand, the recovery was significantly better in SHR females than in SHR males. It may be concluded that the hearts of female SHR are more resistant to ischemia/reperfusion injury as compared with male SHR. This fact could have important clinical implications for the treatment of cardiovascular disease in women., J. Bešík, O. Szárszoi, J. Kuneš, I. Netuka, J. Malý, F. Kolář, J. Pirk, B. Ošťádal., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

407. Transgenic reporter mice with promoter region of murine LRAT specifically marks lens and meiosis spermatocytes

Creator:
Dana Průková, Ileninova, Z., Antosova, B., Petr Kašpárek, Gregor, M., and Radislav Sedláček
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article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, oči, physiology, eyes, LRAT, transgenic mouse, retinol, testis, spermatocyte, sertoli cell, lens, 14, and 612
Language:
English
Description:
Lecithin:retinol acyltransferase (LRAT) is the major enzyme responsible for retinol esterification in the mammalian body. LRAT exhibits specific activity in the cells with active retinol metabolism where it converts retinols into retinyl esters, which represents the major storage form of retinol. Besides hepatic stellate cells in the liver, LRAT appears to have a key physiologic role in several other tissues. In this study, we generated a transgenic reporter mouse expressing green fluorescence protein (EGFP) under the control of region containing -1166 bps from promoter upstream from the putative transcriptional start site and 262 bps downstream of this start. Transgenic reporter mice exhibited specific expression in eyes and testes. In eyes, expression of EGFP-reporter is found in lens and lens epithelium and fibers from embryo to adulthood. In testes, LRAT-EGFP reporter is expressed both in Sertoli and in spermatocytes marking initiation of spermatogenesis in prepubertal mice. Our data show that the examined LRAT regulatory region is sufficient to achieve strong and selective expression in the eye and testes but not in liver and other organs., D. Prukova, Z. Ileninova, B. Antosova, P. Kasparek, M. Gregor, R. Sedlacek., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

408. Transient hypertension and sustained tachycardia in mice housed individually in metabolism cages

Creator:
Hoppe, C. C., Moritz, K. M., Fitzgerald, S. M., Bertram, J. F., and Evans, R. G.
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, myši, stres (fyziologie), hypertenze, sex, physiology, mice, stress (physiology), hypertension, metabolic cage, 14, and 612
Language:
English
Description:
The novel environment of a metabolic cage can be stressful for rodents, but few studies have attempted to quantify this stress-response. Therefore, we determined the effects on mean arterial pressure (MAP) and heart rate (HR), of placing mice of both sexes in metabolism cages for 2 days. After surgical implantation of a carotid artery catheter mice recovered individually in standard cages for 5 days. Mice then spent 2 days in metabolism cages. MAP and HR were monitored in the standard cage on Day 5 and in metabolism cages on Days 6-7. MAP increased by 18±3 and 22±4 %, while HR increased by 27±4 and 27±6 %, in males and females, respectively, during the first hours after cage switch. MAP decreased to baseline in the fourth and eighth h following metabolism cage switch in males and females, respectively. However, HR remained significantly elevated in both sexes during the entire two-day period in metabolism cages. Females had lower MAP than males both pre- and post- metabolism cage switch, but there were no sex differences in HR. These results demonstrate sustained changes in cardiovascular function when mice are housed in metabolism cages, which could potentially affect renal function., C. C. Hoppe ... [et al.]., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

409. Tumor necrosis factor α in various tissues of insulin-resistant obese koletsky rats: relations to insulin receptor characteristics

Creator:
Hřebíček, A., Rypka, M., Chmela, Z., Veselý, J., Magdaléna Kantorová, and Věroslav Golda
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article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, tumor necrosis factor α, insulin resistance, insulin receptor protein tyrosine kinase activity, 14, and 612
Language:
English
Description:
Tumor necrosis factor a (TNFa) was found to be significantly increased in skeletal muscles and retroperitoneal fat of obese insulin-resistant Koletsky rats as compared to control Wistar rats. This increase was accompanied by a depression of insulin receptor protein tyrosine kinase (PTK) activity. Neither the insulin-binding capacity nor insulin receptor affinity were related to this TNFa increase in these tissues. In the liver, no significant changes of TNFa content and only a lowering of insulin-binding capacity were found. It is concluded that an increased TNFa content in muscles and fat (but not in the liver) contributes to insulin resistance by lowering insulin receptor protein tyrosine kinase activity, while other insulin receptor characteristics (insulin-binding capacity and affinity of insulin receptors to the hormone) do not seem to be influenced by this factor., A. Hřebíček, M. Rypka, Z. Chmela, J. Veselý, M. Kantorová, V. Golda., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

410. Urotensin II-induced increase in myocardical distensibility is modulated by angiotensin II and endothelin-1

Creator:
Fontes-Sousa, A. P., Pires, A. L., Monteiro-Cardoso, V. F., and Leite-Moreira, A. F.
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, myokard, physiology, myocardium, urotesin II, angiotensin II, endothelin-1, myocardial distensibility, 14, and 612
Language:
English
Description:
Endogenous regulators, such as angiotensin-II (AngII), endothelin-1 (ET-1) and urotensin-II (U-II) are released from various cell types and their plasma levels are elevated in several cardiovascular diseases. The present study evaluated a potential crosstalk between these systems by investigating if the myocardial effects of U-II are modulated by AngII or ET-1. Effects of U-II (10-8 , 10 -7 , 10 -6 M) were tested in rabbit papillary muscles in the absence and in the presence of losartan (selective AT1 receptor antagonist), PD-145065 ( nonselective ET-1 receptors antagonist), losartan plus PD-145065, AngII or ET-1. U-II promoted concentration-dependent negative inotropic and lusitropic effects that were abolished in all experimental conditions. Also, U-II increased resting muscle length up to 1.008±0.002 L/Lmax. Correcting it to its initial value resulted in a 19.5±3.5 % decrease of resting tension, indicating increased muscle distensibility. This effect on muscle length was completely abolished in the presence of losartan and significantly attenuated by PD-145065 or losartan plus PD-145065. This effect was increased in the presence of AngII, resulting in a 27.5±3.9 % decrease of resting tension, but was unaffected by the presence of ET-1. This study demonstrated an interaction of the U-II system with the AngII and ET-1 systems in terms of regulation of systolic and diastolic function., A. P. Fontes-Sousa ... [et al.]., and Obsahuje seznam literatury
Rights:
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